1. Field of the Invention
The invention relates to a device for influencing the air flow in the area of the roof opening of an openable motor vehicle roof having a wind deflector which is located in the area of the front edge of the roof opening, being pivotably coupled to the roof-mounted frame so that it can be raised into an operating position under the influence of a spring force.
2. Description of Related Art
Devices of the above-mentioned type are currently being used in most vehicles with an openable roof in order to deflect the air flow which streams over the motor vehicle roof during driving of the vehicle so as to reduce the wind noise which arises when driving with the motor vehicle roof open.
Moreover, in particular, in motor vehicles with a roof opening which can be closed by means of a sliding or sliding/lifting cover, it has been shown that, especially for covers which are opened wide or completely opened, low frequency air vibrations are formed. At certain motor vehicle speeds, the vehicle interior acts as a resonator so that air vibrations with considerable intensity can develop, and they are generally perceived as very disturbing by the passengers; the term xe2x80x9crumblingxe2x80x9d has been coined for this type of noise by specialists.
Since both the formation of disruptive airstream noise and the occurrence of rumbling depend on many parameters which can change continually as the vehicle is operating such as, for example, the degree to which the roof is opened and the vehicle speed, it has been found to be a good idea to provide wind deflectors in which the flow conditions can be changed during vehicle operation. Thus, for example, published German Patent Application DE 198 09 943 discloses a wind deflector for a motor vehicle roof with a movable cover for selective closing and at least partial clearance of a roof opening, and the wind deflector is located on the front edge of the roof opening and under the influence of the spring force can be swung into a position in which the wind deflector is lowered into a neutral position by means of laterally arranged raising means which are coupled to be able to swivel on a roof-mounted frame and by moving the cover into the cover closed position. Underneath the movable cover there is a movable sliding headliner for which there is a drive which is independent of the drive of the cover. The wind deflector is coupled to the drive of the sliding headliner such that, with the wind deflector raised, the degree of raising of the wind deflector can be changed by means of the drive of the sliding headliner. Although, with the wind deflector known from German Patent Application DE 198 09 943, the incident flow conditions can be individually varied, this device is disadvantageous in that the sliding head liner must be moved to adjust the angle of inclination of the wind deflector. In the known device, thus, what otherwise would be two fundamentally independent parameters are linked to one another. Specifically, on the one hand, the development of wind noise which can be influenced by means of the wind deflector, and on the other hand, the light incidence through the cover element which can be adjusted by the sliding headliner, and which is generally made of a transparent material when using a headliner element no longer can be independently adjusted.
In view of the problems which arise in devices known from the prior art, an object of this invention is to devise a device for influencing the air flow in the area of the roof opening of an openable motor vehicle roof, by means of which the incident flow conditions of the air flow streaming over the motor vehicle roof can be changed at will without other functions of the roof being adversely affected.
In a device for influencing the air flow in the area of the roof opening of an openable motor vehicle roof with a wind deflector which is located in the area of the front edge of the roof opening and which is pivotally coupled to the roof-mounted frame and can be raised under the influence of the spring force into an operating position, this object is achieved in that there is at least one stop which is independent of the adjustment mechanism of other movable roof components in order to limit the raising motion of the wind deflector, and furthermore, there is an adjustment device for changing the position of the stop, and thus, the degree of opening of the wind deflector. In the approach suggested here, thus, the angle of inclination of the raised wind deflector can be adjusted by positioning the stop for the spring-loaded wind deflector without, in doing so, having to change the setting of other movable roof components, especially a cover element which is provided for closing or at least partially exposing the roof opening or a headliner element which may be present under it.
Preferably, the stop is vertically adjustable so that conversion of the direction of action of the adjustment motion of the stop with respect to the wind deflector need not take place.
Especially in motor vehicle roofs with a movable cover element for selectively closing or at least partially clearing the roof opening, in which the cover element is guided along rails or the like which run along the roof opening, the adjustment means is preferably located in the roof-mounted frame in the area of the front edge of the roof opening so that any adverse effect of the displacement motion of the cover element is precluded from the start or can be prevented with relatively simple means.
The stop process takes place, preferably, by means of an actuating motor, according to one preferred embodiment, the adjustment means comprising an electronic control arrangement for triggering the actuating motor depending on pre-adjustable or freely selectable parameters so that the degree of raising of the wind deflector can be automatically adapted to the respective operating situation. In particular, there can be sensor technology coupled to the electronic control arrangement for acquiring the motor vehicle speed and/or the degree of roof opening, and in many cases, components already present on the vehicle can be used, for example, the vehicle speed signal which is provided anyway by the vehicle electronics and the position signal of the cover element which is provided by the drive motor of a cover element which is provided for closing the roof opening. As an alternative to a sensor for acquiring the vehicle speed, there can also be a sensor for determining the airstream speed when driving or the dynamic pressure.
In another embodiment of the invention, there can be several stops, in this case, the adjustment means comprising a lever mechanism in order to simultaneously adjust the position of all stops. In this way, the wind deflector can be set more uniformly over the entire width of the roof opening. Unwanted wobbling movements of the wind deflector as could occur when there is only one stop, especially at higher speeds, are effectively prevented by providing several stops. Here, the lever mechanism can have two essentially mirror-symmetrical lever components which are coupled in the area of the front edge of the roof opening such that one end of each lever component forms a stop for the wind deflector, while the other end of the lever component is coupled to the adjustment means, especially to the actuating motor. Preferably, a driver is mounted on the wind deflector and it interacts with a stop, in this case, it being especially advantageous if the driver is mounted on a pivoting lever arm which interacts with the wind deflector and there being an abutment which counteracts the pivoting of the lever arm when the stop engages the driver in order to limit the degree of opening of the wind deflector, but which allows pivoting of the lever arm when the wind deflector is lowered into its neutral position. In this embodiment of the proposed wind deflector device, the construction height of the device can be minimized; this is important especially in motor vehicle roofs in which the wind deflector is made to be lowered into a fixed roof frame which surrounds the roof opening. These embodiments are used especially in motor vehicle roofs which have a roof opening provided in a fixed roof surface and a cover element for closing or at least partially exposing the roof opening, for example, sliding roofs or sliding and lifting roofs, and the wind deflector device being made such that the wind deflector, in its neutral position, is lowered into the roof-mounted frame surrounding the roof opening and the cover element covers the wind deflector when the roof opening is closed.
In this motor vehicle roof, it is especially advantageous if there is at least one hold-down which is connected to the cover element and which provides for the lowering of the wind deflector during the closing motion of the cover element.
The invention is explained in greater detail below with reference to the accompanying drawings which show a preferred embodiment of the invention.